Immunotherapy of Cancer: anti-tumour immunity, escape mechanism and principles of immunotherapy Flashcards
What properties do cancer cells have behaviour wise that normal cells dont do?
Rapid uncontrolled growth Increased mobility Invade tissue Evade immune system Metastasize
How is immunodeficiency and cancer linked?
Imbalance in immune system or inflammation conditions can lead to tumour formation including colon cancer, lymphoma etc…
Tumour cells infiltrated with lymphocytes however, there are anti-tumourigenic effects
What are the body’s way of defending the body against cancer?
Anti tumour responses e.g. CD8+ and CTLs
Production of immune memory
Specificity of individual tumours due to tumour antigens
What will happen if CD8 and CTLs specific to a tumour is injected into another mouse?
Tumour cells not killed since CD8 and CTLs are specific to prev cancer antigens
What is tumour immunoserveillance?
Immune system esp lymphocytes continually recognise cancerous and pre-cancerous cells leading to elimination before they can cause damage
Why do tumour develop despite tumour surveillance?
Tumour surveillance isn’t perfect
What is immunoediting and the 3 phases in it?
Better way to say tumour surveillance
Elimination
Equilibrium
Escape
What are the steps in tumourigenesis?
normal cells undergo change and develop abnormal tumur antigens after exposure to carcinogens and develop into tumour cells
Tumour cells release danger signals such as extra-cellular matrix products leading to immunoediting
What happens in elimination stage of immunoediting?
Rapid response from innate system (NKs NKTs, macrophages and dendritic cells)
Interferon gamma and cytokines lead to tumour death
Tumour specific DCs activate adaptive immunity in draining lymph nodes allowing tumour specific CD8+ and CD4+ to join
What happens in the equilibrium stage of immunoediting?
Elimination phase is incomplete so tumour cels lie dormant and may module tumour antigen expression and stress signals. Immune system only eliminates susceptible clones to prevent tumour expansion by changed tumour cells are selected for
What is Darwinian selection in equilibrium?
Immune system kills cells with antigen similar to original one, due to tumour hetergeneity, some cells that avade immune system killing do not get killed
What happens in the escape phase of immunoediting?
Immune system is unable to control tumour growth leading to tumour progresison
What is immunomodulation?
Manipulating immune response to target cancer - immunotherapy for cancer
